[cgrey8]

Does anybody know of a website or retailer that allows you to enter a part number of some random part (starter, gasket, etc) and get a list of all make/model/year/vehicle/engine/trim combinations that indicate they use that part?

Junkyards have a paid-for database they use for doing something similar, but not quite the exact same thing. For them, you enter a specific vehicle and component, and they'll list all the other vehicles that also used that part. But that's not starting with a part number, that's just saying I have a 2000 Ford Mustang V8 and I need a starter. What all other vehicles used a compatible starter.

I was just curious if there was such a thing for part numbers. Specifically what I'm running into is there are multiple different, but similar, PCV valves at the auto parts store. Back when I selected one, I just picked the first one that had an elbow on it since that worked most conveniently for me. But then I noticed on a recent visit, that there were 3 different part numbers for an identically-looking PCV...each with different vacuum activation/deactivation points and flow rates. And that got me to wondering how I might go about determining the differences and which is really best suited for my particular build. Doing some research, it turns out that nobody publishes tech info on their PCVs. So it's a huge guessing-game. But it might be telling for me to determine the engines each were used in and from there, I might be able to make some educated assumptions. So I wanted to take each of those PNs and find out, for example, is one meant only for L4s, another V6s, and another V8s.

During that research, I did find that someone makes a dual flow tunable PCV for about $130. It's a nice looking setup that I see why is as expensive as it is, but no thanks. It ain't that important to me. I can buy all 3 and play around a lot cheaper than that. It does have the dual flow feature which is neat, but just not that important to me. Although I would like a PCV that has a weak enough spring in it that it isn't going to be trying to flow during idle conditions.

[skunk]

Have you tried Rock Auto's part number search? It is usually pretty good at listing all vehicles and interchange options for aftermarket parts. As for it's accuracy....I have no idea.

Not sure what your wanting to do or working on but the valves I've used have no springs.....just a ball to not allow backflow into the crankcase at very low vacuum and positive pressure at the intake. I'm not sure why you would try to stop the flow idle....since that vacuum is usually maximum and very close to your cruise vacuum....Lol, I may have just answered my own question.....maybe you only want it to open when engine breaking?

John

[cgrey8]

Yeah, those that use the ball are boost-compatible PCVs. Boost-compatible PCVs do usually make use of a ball which does a much better job of preventing "back-flow" during boosted conditions.

The ones I'm referring to have a weight and a very weak spring on top of the weight and I'm pretty sure are NOT positive pressure complaint.

With these, low differential pressure (i.e. in your hand or at WOT conditions), the weight falls to the bottom of the PCV case where the inlet is. Based on how the weight is shaped and lands against the lower orifice, it doesn't appear to seal, but it does obstruct. And a low differential pressure conditions, it doesn't take much obstruction to slow air flow.

As the differential pressure increases (i.e. vacuum increases), the weight is floated off the bottom of the PCV, but the spring keeps it from being sucked all the way to the top. It's during this "floating-of-the-weight" period that the PCV flows the most air. Most of the time the differential pressure is produced by the vacuum in the intake plenum. However at WOT, it's possible for blow-by to be enough to positively pressure the crankcase (relative to atmosphere) and thus the PCV is there to give that pressure somewhere to go so it doesn't vent to atmosphere (an EPA/emissions concern but part of the intent of crankcase ventilation strategy).

Under heavy differential pressure (i.e. heavy vacuum), the crank case pressure overtakes the spring, pushing the weight to the top of the PCV, thus plugging or nearly plugging flow (much more than just an obstruction). It's my understanding that if the PCV is operating correctly, almost all flow should be stopped as long as the differential pressure is enough to hold the weight in place. The top of the weight is supposed to be cone or pintle-shaped so it seats and thus plugs the upper orifice of the PCV. The weight doesn't drop down until the differential pressure lowers enough that the spring can push the weight off the seat which allows flow again.

My intent is I don't want a lot of flow from the PCV during idle...only at cruise and acceleration. Despite the crankcase pulling from metered air, there's still a lag between when air flow rate changes at the PCV and when it changes change at the crankcase's inlet where the MAF is measuring flow. For my setup, that inlet is a hose between the intake track and the PS valve cover. This lag is one of the two causes of idle jitter from crank case ventilation. The other is AFR jitter where the engine is sucking in unburned fuel (blow-by) from the crankcase which is compensated for by the HEGOs, but then once the crankcase is fully evacuated, the PCV air is not nearly so fuel-rich, and thus the EEC has to then adjust the AFRs back down...and I see this in my logs where MAF and RPM haven't changed, but the WB and thus the LAMBSEs are chasing changes at idle immediately after a stop.

So having a PCV that chokes or completely blocks flow during idle would eliminate the PCV being a source of air and AFR jitter. Again I don't know that what I'm seeing is coming from the PCV, but I'd like to eliminate it as a possibility which led me to where I'm at now.

I'm pretty sure the 3 PCVs I see that are shaped identically, but have different part numbers, visually different weights inside, and audibly different sounds when shaken are different because the target differential pressures where they block and allow flow are different. Like I said, knowing what engines were intended to receive which parts might give me some insight into each PCV's flow characteristics.

[skunk]

Interesting....... I always thought of them to be more like a check valve. At low vacuum and positive pressure the PCV closes or restrics enough for crankcase flow to reverse and be drawn from the valve cover to the intake tract pre throttle plate and not to atmosphere. I suppose in my mind the type with the spring did the same and only closed on the crankcase side seat.

I have also experienced what you described and found disabling ARCHSW helps by taking FKARCH out of the equation to dial in fuel at idle. Once it's dialed in re-enable it and adjust FKARCH to get desired results. Smaller numbers lean, larger enrich. If your getting a rich spike off throttle it's possible reducing FKARCH will help. I have to emphasize that idle fuel has to be dialed in with ARCHSW disabled for this to work.

Lol..... I should know better than giving you tuning advice. Your posts are always informative and you have done so much for the community with GUFx. I thank you........ So I'm just throwing it out there.

John

[EDS50]

Are you actually using the plastic elbows on the pcv valves? We always remove them and connect the vacuum line directly to the port on top of the pcv and completely eliminate the elbow. You can use a 80s turbo coupe or grand national pcv as they seal the best. If your pcv is configured in a true sealed system, I would suspect your egr leaking over the pcv.

[EDS50]

Regarding your initial parts question have you tried a simple google search to see what comes up? (not being a wise ass)

[cgrey8]

...I have also experienced what you described and found disabling ARCHSW helps by taking FKARCH out of the equation to dial in fuel at idle. Once it's dialed in re-enable it and adjust FKARCH to get desired results. Smaller numbers lean, larger enrich. If your getting a rich spike off throttle it's possible reducing FKARCH will help. I have to emphasize that idle fuel has to be dialed in with ARCHSW disabled for this to work...

I'll revisit this, because I honestly can't remember if I've paid any attention to that or not.

Are you actually using the plastic elbows on the pcv valves? ...

Yes. I purposely chose one in the line-up of PCVs with the plastic angled topper just because it made routing the hose more convenient given where it is and where the hose needed to go.

Regarding your initial parts question have you tried a simple google search to see what comes up? ...

I just assumed that wouldn't pull up anything useful, but I'll try.

[cgrey8]

Interestingly, I found what my problem was. It was actually PCV related. But it wasn't the actual PCV valve. When I did the 331 swap, I installed an in-line oil separator like what goes on pneumatic lines in my PCV line thinking that would help catch oil blow-by and keep it out of the intake. Sadly it was a complete fail and I deemed it that very shortly after installing it. It collected oil, but it never collected enough to bother draining. Most of the oil that came into it passed right on through it. Well, that thing eventually clogged. And when it started getting a little restrictive, the oil started getting more and more contaminated with water. At that point, it really sludged-up in the line and inside that thing to the point it'd barely flow anything at all. But when it did, it was erratic and irregular as sludge blocked and cleared the passage. Removing that restored engine operation to it's once solid and stable state. While at it, I also checked the valve and it was just fine.

Fortunately I run fully synthetic so no real damage done to anything...just an annoying failure of an already useless part that, to be honest, was installed in an application it was never intended to go in. So ultimately I was the problem.

But to follow up on PCV findings, I never found anything useful or meaningful as it related to this entire topic of discussion.

[EDS50]

Which separator were you using? If it was a generic HD or Lowe's unit; those are water separators...Not oil separators. Oil separators really aren't required on n/a applications. If you are experiencing blow by enough to require a separator on your combination, I would look into upgrading your crankcase evacuation or piston rings. What you were collecting in your set up was most likely oil vapor and condensation. If you feel all is well and you need an oil separator...Look into a Steeda or UPR unit.

[cgrey8]

It was a super-cheap in-line pneumatic separator and I believe it probably was intended to be a water separator. I only installed it because I saw how oily the stock intake was on the 302 when I pulled it. I thought it'd help with the new 331, but it didn't really do much nor did it ever collect much.

But no, I don't believe there's a problem. It was me thinking it would be more useful than it ended up needing to be. In hindsight it wasn't necessary at all. And it's no longer a problem.

[EDS50]

I tried one of those units once on my 89 long ago. The crankcase pressure exploded the plastic bowl and filter to pieces...lol

[cgrey8]

I tried one of those units once on my 89 long ago. The crankcase pressure exploded the plastic bowl and filter to pieces...lol

I'm assuming you were heavily boosted.

[EDS50]

The 89 only made 13# but with the tired bottom end it was more than enough to cause issues with the pcv system.